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Final rule.
We are adopting a new airworthiness directive (AD) for MDHI Model 369A, 369D, 369E, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters. This AD requires inspecting each main rotor blade (MRB) for a crack. This AD was prompted by reports of cracked MRBs. The actions of this AD are intended to address an unsafe condition on these helicopters.